Dental hand piece



July 27,` 1948. M. s'rAuN'r DENTAL HAND PIECE Filed Sept. 15, 1945 parts .throughout the-several` views.

Patent'ed July 27, 19483 UNITED` s-TATS c anasat oEN'rAL HAND PIECE staunt, ohiagjm; i

psntaom September 1a, 1945, sriarNccleglcc i i (01..312-f28) V t Thel present inventionrelates to=denta1-V hand pieces, and is partcularly concerned with dental hand.` pieces of thetype which are to. bo driven by means of a belt and= pu-ll'ey, and Whichiincludes a suitable. chuck lfor hoid'ingthe various drills, hurrs, sandingwheel's, etc. used dental hand pieces. i

One of the objects of' the inventionffiis the provision of an mproved den-tal handip'iece of the class d'escribed in. which improved vforms of bearings are utilized, which by virtueot the particular material utilized" in. the spindiie perm-itthe use of relativel'y smalll beari'ngs, but thel` hearings may be used for a longl peri'od of' time Without s'ubstantiai wear. i

Another object of the lnvent'on isthe provision of an improved externalI handle structure includin'g`` serrated ribs and 'partialiyA` ci'rcul'ar g'rooves which improve the sani--tation` of the hand piece `vby reason of the fact that the g-roovesare-` rnore easily cleaned than the devices of 'the-prior art.

Another' ob'ect of the i-'nvention is theiprovision of an `irnprovedpuley structure for such hand pieces, in which provision is made-topmvent the spllashin-gr of thel oiiand for` the quick removal ofv the pull-cy by mean-s of' 1aith-read'ed gland that holds the tightcnir'ig rod and` threaded shaft. i

Another obect ofA the in-Vention is theprovvision of an improvedl` wrifist joint structure, in-

Vision of an improved stop, for' l-imitiilgrota'tive motion at the wr-ist joint, ai]i of the; parts* of'which arehoused in suitable recesses so that' there are no proiecting -pa'rts and there are no sharp parts which rub against-thebel-t and tend to 'Weaiv` it.

Other objects and advantages' of the ihven- -tion will be a'pparentfrom the following description and the accorrrpanying drawi-ngs, in which similar characters of reference indicate lsimilar A vdivisional appiication, Serial Number M561 has 'beenfilegi on February 4a 1948.

Referring to the single Sheet of dra/wings,

prof-,cream includes; a sheath. ft t;

a cfstaihessrsteet or carbcnsteel, 'hay' 'Ehe rideez i porittcrxs` mi: ctzlmdrical `surface z fFig. 1 is. a. 'side,,'el'etrationa1` ;view cia entaithand pieceembodymg'myf'interrtiom i t- Fig. 2; is, a 'feat-nneni'zary` aiasecti'onaiview: :of the peratinev end offf thehand piece; i

i ma 3. is. zanother-f'fraementary `axial.;sectiImal view `ofswthe rear end; porn-cm or' the handaipece;

Pig. 4 is a fragmentem ;sectiona'litievofitaken on a plane passine through: theviaxis .ithefpulleys, is:. tha planie alongt1re lfinteu=it+4 :of F'g.4 i -1 ;g 'w a HThe dental: hand piece emhodyi'cgvmmnvention is shown in side eievaima inxFi'. mdfis indicated in its emtirety `ty: the numeral litr It may'iczcnpreierahly made a azxal bore Ii'2 and an external cylindrical uzr 1]'3 hiahrcviderl; with'ammtihhcitr 0 rr...

art sarallelgzrooves HL` i i 'b ,twe the emo-tes are motorem-r fk; 'ne slippingf'srip withthe z neerstfandftha 'Or'i'oi eroores a dri'hs le atds; char me the cperatcr'tcz erinthehendip, t Ce. o then 'silinfping. Thepertialy circuler of the erys N permits them to be cleaned Incr asii ;as the lost ,k. o .i H ti nreterehr co sists ei i? metal -memberr the `exterrta'ti.surzfacs .ich ar'e tapered at |8 and IBJtcwcatd the spamer-id, whch-fhasaboreimt;

carina tor the `sctcfle' which has aromat mentam` externat firustoconica. .isurface `23.z y' i :The front; hearing member ia'so ani :annzular shoulder 24 against which the endzoi'thersheath it abuts when tt: is; threaded home 11W: i, eans of i the threads ;15.511 Hi.: '8. At one side. the h -ontshearimg memhen is preferablyx provided withafifi'hradber tthasle abered a .e counterhore Zzhztthich 'serweaas a front end .40``

in a frusto-conical surface 28 for engaging one'v end of the collet 29.

The front bearing member |1 is provided with 'a a cylindrical bearing sleeve lla, having'a fric- 4 ishing Ithe size of the slots 34, 35, while the collet grips a shank.

The spindle bore 21 also houses the tightening rod 44, consisting of an elongated metal rod having a plane end surface 45 for abutting against the end 42 of the plunger di. Adj acentthe end 45 the tightening rod 44 has a cylindrical enlargement 46, which has a sliding fit in the spindle bore 21 and centers the tightening rod at this end. 'At its opposite end in Fig. 3 the tightening rod 44 has a threaded portion 41, the threads of which are complementary to the internal threads 48 in a threaded gland 49, the threaded portion j 5ll=v of which engages lthe internal threads 5| in tional fit in a complementary recess located' at the cylindrical end portion of the front bearing member l1, that is, at 'the right end, rbeneath ff vsuch as, for example, Ifive `thofusandths .of an inch thick. This chromium covered steel spindle may be ground down until its chromium covering is substantially three thousandths in grinding the spindleto fit the bearings. l

i The bearing sleeve [1a is preferably constructed of a hard alloy, and such a combination of chromium plated spindle and hard alloy bearing is adapted to give long use with a minimum amount of wear or vibration.

The collet 29 is adapted to grip the stem of a burr or the shank of a sanding wheel, or any other tool; and it consists of 'a substantially tubular metal member having the external cylindrical surfaces 30, 3|, 32. i

The collet -29 has a cylindricalthrough bore 33, which is approximately the same size as the shank which it is intended to receivefhaving a close sliding fit with the shank. Each end portion of the collet is provided with a plurality, preferably three, axially extendingZ slots 34,` 35, the slots beingequallyspaced in an angularsense and separating the end portions of the 'collet into three separate legs. i i i The external body of -thei'collet is preferably grooved'or relieved at136 and 31 adjacent the end portions so Vas V'to increase the'fiexi'bility of the legs, whichfare' formed by the slots 34, 35 adj acent the base of the slots. At each end of the collet there is a tapered or frusto-conical portion 38, 39, which when engaged -by a complementary frusto-conical surface may tend to cause the end portions of the collet to contract and to grip a shankl in the bore 33. f

The frusto-conical surface on the front-end of the collet at 33 engages the complementary frusto-conical surface 28 inside' the spindle. The frusto-conical surface '39 at the other end of the collet, that is, the right end (Fig. 2), engages a complementary inner frusto-conical surface 40 Von a'plunger 4|.

The plunger 4| merely consists of a cylindrical metal member having a s-liding fit in the bore 21 of the spindle 22. The right end 42 of the plunger may have a plane surface. while the opposite end prefera'bly has a' bore 43, and the annular end surface terminates in the frusto-conical surface 40. previously mentioned. ,v l i o The natural tendency of the colletis for its en'd portions to spring outwardly into cylindrical form; but, when forced toward the left. in-Fig. 2 by the plun'ger 4| theV end portionsjof the collet are cammed inwardly toward each othendimin--f` the end of the tubular spindle 22. A vsteel knob 52 may be threaded on the end I of the tightening rod M b-y means of 'a threaded bore 53, and may be secured in place by being soldered to the rod 44 or by a frictional pin 54, which passes through both the knob and the threaded portion of the tighteninglrod 44. The cylindrical edge surface55 of the knob 52 is preferably knurled, and the length of the length of the threaded portion 41 is such as to permit longitudinal adjustment of the tightening rod 44 by,means of its threads 41. i i i The gland 49 has a radially extending flange provided with a cylindrical knurled surface 56, but at two diametrically opposite points on the gland 43 there are parallel flat surfaces 51 for engagement With a small wrench.

'The spindle 22 (Fig. 3) may be provided with acylindrical thrust ring 5'8v pressed on the spindle, and has an annular surface 53 serving as a thrust bearing. Beyond the thrust surface 59 and toward the right in Fig. 3 the spindle 22 has a reduced cylindrical portion 60, which. serves as a trunnion for engagement -in `the cylindrical bore 6| of the rear bearing 62.

This rear bearing member 62 is also preferably constructed of hardened steel or bronze, and is provided with an annular lubricant groove V63 communicatingwith a radial aperture 64.. This aperture communicates with a plurality of radially extending apertures 65, regularly spaced about ,the'periphery of the rear bearing member 63.-

drical threaded member 61 adapted to be received in the threaded bore 68`of the wrist joint frame. At the left, beyond the wrist joint frame, the rear bearing 62 has an ,en'larged cylindrical ,portion 69, which has a substantial fit in the cylindrica1bore|2 of the sheath I l.V ``The bore 6| of the rear bearing 62 communicates with an enlarged counterbore 410, beginning at the Vthrust washer 58, where there is an annular thrust surface 1| engaging the'thrust surface 59 on the thrust washer 58.

To the left of the thrust washer 58 the spind'le. 22 is substantially smallerthan the bore 10 in the rear bearingv 62 `or the bore-l2in the sheath Il. The cylindrical skirt 12 on the rear bearing 62 extends into an enlarged counterbore 13 the sheath ll, and the length `of these two The leaf spring is preferably securedfin ,a groove |30 by having a screw bolt 13| pass through the end of the leaf spring, the bolt being threaded into the arm |22. At its end the tubular arm 122 has an axially extending, partially'annular portion |32, which engages in a slot complementary to it on the arm, to which it is attached, this arm having a shank that passes into the .bore l2'l, and having a hole for receiving the end of the spring |29.

The wrist joint swivel frame HS is shown in section in Fig. 4, and this frame also serves to support a pair of pulleys |33, |34, by means of a wrist joint 'pulley stud |35. The body of the wrist joint pulley frame |l has a through 'bore R36, into which the stud 35 is forced, the stud being provided with axially extending knurled formations by means of which it is secured .against rotation with a pressed fit. Ateach end the pulley stud has a reduced cylindrical portion |3`l, which serves to receive a thrust washer [38 that spaces the pulley from the frame U5, and is engaged by the pulley shaft.

i The pulley stud |35 has each end provided with a reduced threaded portion |39, which is adapted to be received in the threaded bore lll ,of the pulley shaft 14|.

The pulley shaft comprises a substantially cylindrical metal member, which has the threaded bore IM), and a smaller counterbore M2 for lubrication, the oounterbore M2 being spun over at its end M3 to retain a steel ball IM, which is urged into engagement with the spun-over portion 143 by a compression spring M5, the' other end of the spring engaging the reduced threaded end l39 of the pulley stud.

The pulley shaft also has a radially extending aperture [46 whereby lubricant which is forced in past the ball IM may gain access to the external cylindrical bearing surface M'i of the shaft 14|. The shaft |4| also supports a .pulley guard 148 in the form of a substantially circular radially extending fiange carried by the pulley shaft |4l, which extends beyond the edge of the pulley 134 and has an inwardly extending cylindrical;

fiange [49 overhanging the outer flange of the pulley.

The guard M8 protects the hands Aof the operator from the pulleys, butit does not interfere with the pulley belt, and the guard also prevents the throwing of oil, which might be carried by the pulley to its outermost edge by centrifugal force.

The pulley guard preferably has an annular thrust surface 150 located to engage the outer end of each pulley so that endwise motion of the pulley on the pulley shaft is prevented, and the pulley has a running fit between the washer 138 and the thrust surface 150.

The two pulleys may be identical in construction, and each consists of a circular metal member provided with a centrally located bearing bore which the hand piece operates more smoothly.

'and may be maintained in most excellent .condition for along period of time without repair.

The pulley is quickly detachable, beingheld in place by a threaded gland which also serves to support the tightening rod by means of which the collet of the chuck may be controlled for gripping the shank of a tool. i The present hand piece has its wrist joint frame adjustably supported in such manner that wear of the bearingsmay be taken up and adequate provision is made for maintaining proper lubrication of the spindle at all times. The wrist joint frame arm is provided witha improved built-in form of st-op which may be more cheaply manufactured, and which hasno projecting parts that might catch on the clothing of the operator. The wrist joint pulleys, are guarded and protected on both sides, and are provided with adequate means for assuring their lubrication at all times and for preventing the pulleys from throwing off lubricant on the operator or the patient. U

The present hand piece may be taken apart very easily for inspection of its parts or .for cleaning, and it is also adapted to be maintained in a sanitary condition with a minimum amount of labor.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit o-f the invention, and I do not wish to be limitedito the precise details of construction set forth,.but desire to avail myself of all changes within the scope of the appended claim. z

Having thus described my invention, what I claim .as new and desire to secure by Letters Patent of the United States, ist i In a dental hand piece, thecombination'ofa chuck tightener rod with a spindle, said spindle comprising a tubular member having a cylindrical bore of substantially larger size than said rod, said rod having an integral enlargement adjacent its free end for centering the rod in said bore, said rod being provided with a threaded portion adjacent its other end and said threaded .portionbeing mounted in a threaded bore in a gland member, said gland member being threaded into the end of said spindle, a `knob threaded on .the threaded end :of said rod, and a transverse pin passing through a part of the knob androd vfor preventing relative rotation between the knob and rod, a wrist joint member having a threaded bore and a relatively hard alloy bearing comprising a tubular member externally threaded to fit in `said latter bore, said bearing having a cylindrical bearing bore for receiving said Vspindle,` a sheath carried by said wrist joint member and surrounding said bearing member, 'saidlsheath carrying at its forward end a front bearing member, said front bearing member having an inner tapered bearing surface, and said spindle having a complementary surface, said spindle being provided with exterior chromium plated surfaces for engaging the bearings, said wrist joint member being formed with an external threaded surface for engaging a threaded sleeve, and said sleeve and sheath having annular Shoulders engaging each other, whereby the sleeve may be adjustably threaded on the wrist joint member to take up and adjust the length of the sleeve with respect to wear on the tapered end of the spindle, the said wrist joint member having a transverse threaded bore, a relatively soft metal block in said bore engaging the threads of the first-mntioned bearing, and a set screw in said transverse -bore engaging said soft metal block to secure the wrist joint member against rotation on said bearing without damage to the threads engaged by said soft metal block. Number MARTIN STAUNT.

REFERENCES CITED The following references are of record in the file of this patent: 10

Johnson Dec. 8, 1891 

